

#import "APLFile.h"

#import "Logging.h"

@implementation APLFile
+ createWithFile:(NSString*)f {
	return [[APLFile alloc] initWithFile:f];
}

- (NSString*)readline:(NSFileHandle*)f { // rather hack-style substitution to fgets...
	NSMutableData* d = [NSMutableData dataWithCapacity:100]; // it will grow, here should be most expected value (may gain few nanosecond from it =) )
	while(true) {
		NSData* byte = [f readDataOfLength:1];
		if(!byte) {
			[f seekToFileOffset:([f offsetInFile] - [d length])];
			return nil;
		}
		[d appendData:byte];
		if(*((const char*)[byte bytes]) == '\n') break;
	}
	NSString* s = [[NSString alloc] initWithData:d encoding:NSUTF8StringEncoding]; //! handle encoding error (in case binary data starts not from newline, impossible on real apl, but who knows...)
	return s;
}

- (NSURL*)urlForPath:(NSString*)path relativeTo:(NSString*)baseFilename {
	NSRange protocolRange = [path rangeOfString:@"://"];
	if(protocolRange.location != NSNotFound)
		return [NSURL URLWithString:path];

	NSMutableString* unixPath = [path mutableCopy];
	if(![unixPath hasPrefix:@"/"]) {
		// Only relative paths would have windows backslashes.
		[unixPath replaceOccurrencesOfString:@"\\" withString:@"/" options:0 range:NSMakeRange(0, [unixPath length])];

		NSString* basePath = [[[baseFilename stringByStandardizingPath] stringByDeletingLastPathComponent] stringByAppendingString:@"/"];
		[unixPath insertString:basePath atIndex:0];
	}
	NSURL* url = [NSURL URLWithString:[[NSURL fileURLWithPath:unixPath] absoluteString]];
	return url;
}

- initWithFile:(NSString*)filename {
	self = [super init];
	if(self) {
		// startBlock must be always >= 0
		NSFileHandle* f = (NSFileHandle*)[NSFileHandle fileHandleForReadingAtPath:filename];
		if(!f) {
			ALog(@"Failed to open apl file '%@' for reading", f);
			return nil;
		}
		NSString* header = @"[Monkey's Audio Image Link File]\r\n";
		NSData* da = [f readDataOfLength:[header length]];
		if(!da) {
			ALog(@"Cannot read header");
			return nil;
		}
		NSString* str = [[NSString alloc] initWithData:da encoding:NSASCIIStringEncoding];
		if([str compare:header options:NSCaseInsensitiveSearch]) {
			ALog(@"APL header mismatch");
			return nil;
		}
		// now read by lines, skip empty, up to line <tagline> (or any starting with '-' - may be other tags can be present)
		NSString* line = nil;
		NSScanner* scanner = nil;
		// NSCharacterSet *whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];
		while((line = [self readline:f])) {
			if(![line compare:@"----- APE TAG (DO NOT TOUCH!!!) -----\r\n" options:NSCaseInsensitiveSearch]) break;
			if([line characterAtIndex:0] == '-') break;
			scanner = [[NSScanner alloc] initWithString:line];
			NSString *field = nil, *value = nil;
			if(![scanner scanUpToString:@"=" intoString:&field]) continue;
			if(![scanner scanString:@"=" intoString:nil]) continue;
			if(![scanner scanUpToString:@"\r\n" intoString:&value]) continue;
			if(![field compare:@"Image File" options:NSCaseInsensitiveSearch]) {
				file = [self urlForPath:value relativeTo:filename];
				DLog(@"APL refers to file '%@' read '%@'", file, value);
				continue;
			}
			if(![field compare:@"Start Block" options:NSCaseInsensitiveSearch]) {
				startBlock = [value intValue]; //!!! bugs with files over 2GB
				// DLog(@"APL start block %d (%@)", startBlock, value);
				continue;
			}
			if(![field compare:@"Finish Block" options:NSCaseInsensitiveSearch]) {
				endBlock = [value intValue]; //!!! bugs with files over 2GB
				// DLog(@"APL start block %d (%@)", endBlock, value);
				continue;
			}
		}
		// check here for EOF? cocoa does not have this functionality :(
		[f closeFile];
	}
	return self;
}

- (long)startBlock {
	return startBlock;
}
- (long)endBlock {
	return endBlock;
}
- (NSURL*)file {
	return file;
}

@end
